President Donald Trump offered Tuesday to help Mexico hunt the killers of nine Mormon women and children shot dead in a lawless border area — and said the United States stood ready to back its southern neighbour in a ‘war’ against the drugs cartels.

Gunmen ambushed the members of the LeBaron family — a large clan of Mormons who emigrated to Mexico in the late 19th century — on a rural road Monday between the states of Sonora and Chihuahua, which border the United States.

Mexican officials said six children were also wounded and another girl was missing after the attack, which left the family’s three cars riddled with bullets and badly charred, as seen in images posted on social media by devastated relatives.

‘If Mexico needs or requests help in cleaning out these monsters, the United States stands ready, willing and able to get involved and do the job quickly and effectively,’ Trump wrote in a tweet.

He praised Mexican president Andres Manuel Lopez Obrador for prioritising the fight against drug trafficking, but said, ‘The cartels have become so large and powerful that you sometimes need an army to defeat an army. This is the time for Mexico, with the help of the United States, to wage WAR on the drug cartels and wipe them off the face of the earth.’

Lopez Obrador said he would accept ‘all necessary cooperation’ to get justice for the victims, all of whom lived on the Mexican side but had dual nationality.

But the left-wing populist, who has declared an end to Mexico’s ‘drug wars,’ said he was not looking for a new one.

‘We don’t agree with Trump on that,’ he told a news conference. ‘War is synonymous with irrationality.’

He later tweeted that he had thanked Trump for his support in a phone call.

The White House said the presidents had spoken about the ‘growing violent behaviour’ of drugs cartels and other criminal gangs.

‘President Trump made clear that the United States condemns these senseless acts of violence that took the lives of nine American citizens and offered Mexico assistance to ensure the perpetrators face justice,’ said spokesman Hogan Gidley.

Shocked, outraged members of the LeBaron family took to social media to call for people’s prayers and condemn the lawless violence gripping much of the border region.

‘It was a massacre,’ Julian LeBaron, an activist who has denounced criminal groups in the area, told Mexican radio network Formula.

He said the women were on their way to the airport with their children when their SUVs were attacked.

Mexican security minister Alfonso Durazo said the family may have been mistakenly targeted or caught in the crossfire in turf wars between rival drug cartels.

He added that the wounded children had been taken to Phoenix, Arizona for treatment.

The LeBaron community are descendants of Mormons who fled the US in the late 1800s after being persecuted for their traditions, including polygamy. Many are dual US-Mexican citizens.

One former member is George Romney, father of 2012 Republican presidential candidate Mitt Romney, who was born in 1907 in Colonia Dublan in Chihuahua state, according to NBC.

Romney said on Twitter he was ‘heartbroken for the victims of the horrific attacks.’

It is not the first time the LeBaron family has been targeted. Julian LeBaron’s brother Benjamin, founder of a crime-fighting group called SOS Chihuahua, was assassinated in 2009 after he led protests over the kidnapping of their 16-year-old brother.

The murder came after the Mormons refused to pay the ransom. The young LeBaron was eventually released.

The region around the 3,145-kilometer US-Mexican border is plagued by violent crime.

Trump, who is battling to build the border wall that was his signature campaign pledge, regularly tells Mexico to do more to fight drug trafficking and illegal migration across the frontier.

Lopez Obrador typically responds that the US needs to crack down on illegal firearms trafficking, which generates an estimated $127 million in profits a year for the American gun industry.

Mexico has registered more than 250,000 murders since the government controversially deployed the army to fight drug trafficking in 2006.

Many experts blame the ‘drug wars’ for spiralling violence, as fragmented cartels battle each other and the army.

Lopez Obrador has struggled to rein in the violence since taking office in December 2018. This year appears on track to set a new murder record in Mexico, with 25,890 so far.